The Connection between Urinary Equol Levels and the Prevalence of Atopic Dermatitis.

BACKGROUND: Soy isoflavones and their metabolites such as equol have been associated with a reduced risk of hormone-sensitive tumors and metabolic syndromes. However, individual soy isoflavones and equol levels in atopic dermatitis remain uninvestigated. OBJECTIVE: The aim of this study is to compare the levels of urinary daidzein, genistein, and equol between atopic dermatitis patients and normal subjects and to examine the correlation between equol concentration and the severity of clinical symptoms. METHODS: A cross-sectional study was conducted at Akita University Hospital and Aso Iizuka Hospital in Japan. Fifty patients with confirmed atopic dermatitis diagnosis and 67 healthy controls were recruited. Daidzein, genistein, and equol in urine were measured by using a high-performance liquid chromatography-mass spectrometry system. RESULTS: Urinary equol levels were significantly lower in the atopic dermatitis patients than in the healthy controls (p = 0.002). The difference was particularly noticeable in young people (6-19 years, p < 0.001). No correlations were found between urinary equol levels and the severity of clinical symptoms and laboratory data in the atopic dermatitis patients. CONCLUSION: Equol levels in childhood might be involved in the development of atopic dermatitis.

Urinary equol, but not daidzein and genistein, was inversely associated with the risk of type 2 diabetes in Chinese adults.

PURPOSE: Many studies have examined the association of isoflavone intake with type 2 diabetes (T2D), and produced inconsistent results. Few studies, however, explored the association using objective biomarkers (particular for daidzein metabolite-equol) of isoflavones. We aimed to explore the association of urinary equol, daidzein and genistein concentrations with T2D and examine the mediating roles of high-sensitivity C-reactive protein (hsCRP) and retinol binding protein 4 (RBP4). METHODS: This prospective study included 2818 subjects. Urinary concentrations of equol, daidzein and genistein were measured by high-performance liquid chromatography-tandem mass spectrometry. The associations between urinary isoflavones and T2D incidence were evaluated by cox proportional hazards model. RESULTS: After adjustment for covariates, urinary equol except daidzein and genistein was inversely associated with T2D incidence. In comparison with the first tertile, multivariable adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for T2D incidence in the second and third tertile of equol concentration were 0.52 (0.37, 0.73) and 0.72 (0.53, 0.97), respectively. In stratified analyses by sex, the HR (95% CI) of men in the second vs. first tertile of equol was 0.29 (0.14, 0.58). Equivalent estimation in women was 0.67 (0.45, 1.01). Neither women nor men in the third tertile showed significant difference of T2D incidence compared with the first tertile. In path analyses, there was no evidence of mediating effects of hsCRP and RBP4 on the "equol-T2D" relationship. CONCLUSIONS: Urinary equol was favorably associated with a decreased T2D incidence in Chinese adults. The equol-T2D relationship might not be mediated by hsCRP and RBP4. TRIAL REGISTRATION: This study has been registered at http://www.clinicaltrials.gov as NCT03179657.

Relationship of equol production between children aged 5-7 years and their mothers.

PURPOSE: The factors responsible for the production of isoflavone metabolites have not yet been identified. We aimed to examine the relationships of equol production between mother and child in a birth cohort in Japan. METHODS: Subjects were a part of the participants in a longitudinal study on pregnant women and their offspring. When children were 5-7 years old, mothers and children were asked to reply to a questionnaire on lifestyles and a 3-day child's dietary record. Mothers and children were given a bar-shaped soy snack (Soyjoy®) daily on two consecutive days (soy challenge). The snack contained 14 mg of overall soy isoflavones as the sum of aglycones and the glucosides for mothers and 7.5 mg for children. On the morning of day 0 and 3, they were asked to mail their first-void urines. Urinary isoflavone metabolites of 159 mother-child pairs were measured by a high-performance liquid chromatography method. RESULTS: Equol producers were 35.5 % among mothers and 13.8 % among children. Equol producer status of a child was neither associated with dietary intake nor with urinary levels of daidzein and genistein. After multiple adjustments for potential confounders, the estimated relative risk of equol producer was 2.75 (95 % confidence interval 1.00, 7.52) among children whose mother was an equol producer, compared with children whose mother was a non-producer. CONCLUSION: Child's equol production was associated with the mother's equol producer status. The effects of maternal factors on child's equol production should be studied further.

Trapping Methylglyoxal by Genistein and Its Metabolites in Mice.

Increasing evidence supports dicarbonyl stress such as methylglyoxal (MGO) as one of the major pathogenic links between hyperglycemia and diabetic complications. In vitro studies have shown that dietary flavonoids can inhibit the formation of advanced glycation end products (AGEs) by trapping MGO. However, whether flavonoids can trap MGO in vivo and whether biotransformation limits the trapping capacity of flavonoids remain virtually unknown. In this study, we investigated whether genistein (GEN), the major soy isoflavone, could trap MGO in mice by promoting the formation of MGO adducts of GEN and its metabolites. Two different mouse studies were conducted. In the acute study, a single dose of MGO and GEN were administered to mice via oral gavage. In the chronic study, MGO was given to mice in drinking water for 1 month and then GEN was given to mice for 4 consecutive days via oral gavage. Two mono-MGO adducts of GEN and six mono-MGO adducts of GEN phase I and microbial metabolites were identified in mouse urine samples from these studies using liquid chromatography/electrospray ionization tandem mass spectrometry. The structures of these MGO adducts were confirmed by analyzing their MS(n) (n = 1-4) spectra as well as by comparing them with the tandem mass spectra of authentic standards. All of the MGO adducts presented in their phase II conjugated forms in mouse urine samples in the acute and chronic studies. To our knowledge, this is the first in vivo evidence to demonstrate the trapping efficacy of GEN in mice and to show that the metabolites of GEN remain bioactive.

Urine phyto-oestrogen metabolites are not significantly associated with risk of type 2 diabetes: the Singapore Chinese health study.

We evaluated the relationship between urine concentrations of phyto-oestrogens (isoflavones and lignans) and risk of incident type 2 diabetes in middle-aged and elderly Chinese residing in Singapore. Urine metabolites of isoflavones and lignans were assayed by HPLC among 564 diabetes cases and 564 matched controls in a case-control study nested within the Singapore Chinese Health Study cohort. Participants were free of diagnosed diabetes, CVD and cancer at morning urine collections during 1999-2004. Cases were participants who reported to have physician-diagnosed diabetes at follow-up visits during 2006-2010, whereas controls were randomly selected among those who remained free of diabetes and were matched to the index cases by age, sex, dialect group and date of urine collection. Conditional logistic regression models were used to calculate OR and 95 % CI with adjustment for potential confounders. The mean age of the participants at the time of urine collection was 59·8 years, and the average interval between urine collection and diabetes diagnosis was 4·0 years. The multivariate-adjusted OR for diabetes were 1·00 (reference), 0·76 (95 % CI 0·52, 1·11), 0·78 (95 % CI 0·53, 1·14) and 0·79 (95 % CI 0·54, 1·15) across quartiles of urine isoflavones (P for trend=0·54), and were 1·00 (reference), 0·87 (95 % CI 0·60, 1·27), 1·10 (95 % CI 0·77, 1·56) and 0·93 (95 % CI 0·63, 1·37) for lignans (P for trend=0·93). The results were similar in men and women, as well as for individual metabolites of isoflavones (genistein, daidzein, glycitin and equol) or lignans (enterodiol and enterolactone). The present study did not find a significant association between urine phyto-oestrogen metabolites and risk of type 2 diabetes in Chinese adults.

Soy isoflavone metabolism in cats compared with other species: urinary metabolite concentrations and glucuronidation by liver microsomes.

1. Soybean is a common source of protein in many pet foods. Slow glucuronidation of soy-derived isoflavones in cats has been hypothesized to result in accumulation with adverse health consequences. Here, we evaluated species' differences in soy isoflavone glucuronidation using urine samples from cats and dogs fed a soy-based diet and liver microsomes from cats compared with microsomes from 12 other species. 2. Significant concentrations of conjugated (but not unconjugated) genistein, daidzein and glycitein, and the gut microbiome metabolites, dihydrogenistein and dihydrodaidzein, were found in cat and dog urine samples. Substantial amounts of conjugated equol were also found in cat urine but not in dog urine. 3. ß-Glucuronidase treatment showed that all these compounds were significantly glucuronidated in dog urine while only daidzein (11%) and glycitein (37%) showed any glucuronidation in cat urine suggesting that alternate metabolic pathways including sulfation predominate in cats. 4. Glucuronidation rates of genistein, daidzein and equol by cat livers were consistently ranked within the lowest 3 out of 13 species' livers evaluated. Ferret and mongoose livers were also ranked in the lowest four species. 5. Our results demonstrate that glucuronidation is a minor pathway for soy isoflavone metabolism in cats compared with most other species.

A combination of soy isoflavones and cello-oligosaccharides changes equol/O-desmethylangolensin production ratio and attenuates bone fragility in ovariectomized mice.

We examined the cooperative effects of isoflavones and cello-oligosaccharides on daidzein metabolism and bone fragility in ovariectomized mice. Cello-oligosaccharides increased urinary equol and decreased O-desmethylangolensin. A combination of isoflavones and cello-oligosaccharides attenuated decreases in bone breaking force and stiffness caused by ovariectomy. Combination treatment with isofalvones and cello-oligosaccharides increases urinary equol/O-desmethylangolensin production ratio and prevents ovariectomy-induced abnormalities in bone strength.

Urinary Phytoestrogens Are Associated with Subtle Indicators of Semen Quality among Male Partners of Couples Desiring Pregnancy.

BACKGROUND: Phytoestrogens have been associated with subtle hormonal changes, although effects on male fecundity are largely unknown. OBJECTIVE: We evaluated associations between male urinary phytoestrogen (isoflavone and lignan) concentrations and semen quality. METHODS: This study was a prospective cohort study of 501 male partners of couples desiring pregnancy and discontinuing contraception. Each participant provided up to 2 semen samples that were analyzed for 35 semen quality endpoints the following day. Linear mixed-effects models were used to estimate associations between baseline urinary phytoestrogen concentrations and semen quality parameters, adjusted for age, body mass index (BMI), research site, and serum lipid and cotinine concentrations. RESULTS: Most associations between urinary phytoestrogens and semen quality parameters were null. However, select individual phytoestrogens were associated with semen quality parameters, with associations dependent on the class of phytoestrogens and modified by BMI. Specifically, genistein and daidzein were associated with a lower percentage of normal sperm and increased abnormalities in semen morphology, with reduced associations observed as BMI increased (P < 0.05) [percentages (95% CIs) of normal morphology by WHO traditional criteria: genistein, main effect: -5.61% (-9.42%, -1.79%); interaction: 0.19% (0.06%, 0.31%) per log unit increase; daidzein, main effect: -5.35% (-9.36%, -1.34%); interaction: 0.18% (0.05%, 0.32%) per log unit increase]. Enterolactone was associated with fewer abnormalities in semen morphometry and morphology and decreased DNA fragmentation, with reduced associations observed as BMI increased (P < 0.05) [percentages (95% CIs) of abnormalities in the neck and midpiece: enterolactone, main effect: -3.35% (-6.51%, -0.19%); interaction: 0.11% (0.01%, 0.21%) per log unit increase]. CONCLUSIONS: These results suggest that male urinary phytoestrogen concentrations characteristic of the US population may be associated with subtle indicators of male fecundity and semen quality but were not associated with couple fecundity.

Urinary isoflavonoids and risk of type 2 diabetes: a prospective investigation in US women.

To examine the association between urinary excretion of isoflavonoids and risk of type 2 diabetes (T2D), we conducted a nested case-control study among 1111 T2D pairs identified during 1995-2008 in the Nurses' Health Study (NHS) and NHSII, who were free of diabetes, CVD and cancer at urine sample collection. Urinary excretion of daidzein and genistein, as well as their metabolites O-desmethylangolensin (O-DMA), dihydrogenistein (DHGE) and dihydrodaidzein (DHDE) was assayed using liquid chromatography MS. Self-reported T2D incident cases were confirmed using a validated questionnaire. Higher urinary excretion of daidzein and genistein was associated with a lower risk of T2D in the combined cohorts. Comparing extreme tertiles of the urinary markers, the OR of T2D were 0·71 (95 % CI 0·55, 0·93) for daidzein and 0·74 (95 % CI 0·56, 0·97) for genistein, although the test for linear trend was not significant for genistein (P trend=0·03 and 0·15, respectively). DMA, DHDE and DHGE were non-significantly associated with a lower T2D risk. The inverse association of daidzein with T2D risk was stronger among post-menopausal women who did not use hormone replacement therapy (P interaction=0·001): the OR was 0·58 (95 % CI 0·34, 0·97) comparing extreme tertiles among these women. In conclusion, urinary excretion of isoflavones was associated with a lower T2D risk in US women, especially among post-menopausal women who did not use hormone. Further research is warranted to replicate these observations among western populations with similarly low overall isoflavone intake.

Soy food frequency questionnaire does not correlate with baseline isoflavone levels in patients with bladder cancer.

BACKGROUND: The isoflavone genistein, a natural soy product with receptor tyrosine kinase-inhibiting activity, as well as phytoestrogenic and other potential anticarcinogenic effects, is being studied as an anticancer agent. Since isoflavones are commonly consumed in food products containing soy proteins, a method to control for baseline isoflavone consumption is needed. METHODS: HPLC was used to evaluate baseline plasma and urine concentrations of isoflavone in fifty-four participants with bladder cancer enrolled on a phase II chemoprevention study of G-2535. The soy food frequency questionnaire was used to assess participant's baseline soy intake. The association between baseline isoflavone concentrations and intakes for genistein and daidzein was assessed by the Spearman's rank correlation coefficient. RESULTS: The majority of participants had no detectable genistein or daidzein in plasma at baseline. The median and range of values were 0 (0-1480) nmol/L for genistein, and 0 (0-1260) nmol/L for daidzein. In urine, the median and range of values were 91.0 (0-9030) nmol/L for genistein and 623 (0-100,000) nmol/L for daidzein. The median and range of weekly estimated genistein intake was 0 (0-236) mg/wk; the median and range of weekly estimated daidzein intake was 0 (0-114) mg/wk. There was no relationship to soy intake as measured by the food frequency questionnaire and baseline isoflavone levels in plasma or urine and the Spearman's rank correlation coefficients were not significant. CONCLUSION: The soy food frequency questionnaire did not correlate with plasma or urine concentrations of either isoflavone. IMPACT: Alternative methods for controlling for soy consumption, including measuring plasma and urine concentrations, in isoflavone chemoprevention trials should be considered.

Urinary phytoestrogens in relation to metabolic disturbances among children and adolescents.

Previous studies have examined whether phytoestrogens affect glucose and lipid metabolism. However, data on children and adolescents are still limited, with most of the evidence pertaining to one phytoestrogen, namely genistein. To investigate the effect of six phytoestrogens [daidezin, enterodiol, enterolactone, equol, genistein and O-Desmethylangolensin (O-DMA)] on metabolic disturbances among youths, a cross-sectional study was conducted using a sample of 2,429 children and adolescents, 6-18 years, from the 2009-2010 National Health and Nutrition Examination Surveys (NHANES). The main outcome measures were body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), high-density lipoprotein (HDL-C), low-density lipoprotein (LDL-C) and total cholesterol (TC), fasting glucose, triglycerides and glycohemoglobin. SBP was inversely related to enterolactone and equol. Triglycerides were inversely related to daidezin, equol, genistein and O-DMA. Whereas TC and LDL-C were inversely related to equol, an HDL-C was inversely related to genistein and O-DMA. Whereas fasting glucose was associated with enterodiol (ß = 0.33, 95% CI: 0.028, 0.63), a positive relationship was observed between enterodiol and risk of HDL-C ≥ 35 mg dl(-1) (ß = 0.04, 95% CI: 0.01, 0.07). In conclusion, certain phytoestrogens may contribute either positively or negatively to disturbances in lipid and glucose metabolism. Large prospective cohort studies are needed to confirm our study findings.

Simultaneous monitoring of seven phenolic metabolites of endocrine disrupting compounds (EDC) in human urine using gas chromatography with tandem mass spectrometry.

A gas chromatographic-tandem mass spectrometric (GC-MS/MS) method for the simultaneous determination of the three well-known endocrine disruptors, bisphenol A, daidzein and genistein, as well as of four human pesticide metabolites which are supposed to have proper endocrine activity or which are metabolites of endocrine-disrupting compounds, viz., 1- and 2-naphthol, 2-isopropoxyphenol and 3,5,6-trichloropyridinol, has been developed and validated. The method involves enzymatic cleavage of the conjugates using ß-glucuronidase/arylsulfatase followed by solid-phase extraction and derivatisation with N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide. Isotopically labelled internal standards were used for all analytes, to achieve best analytical error correction. The method proved to be both sensitive and reliable in human urine with detection limits ranging from 0.1 to 0.6 µg/L for all analytes. Precision and repeatability was determined to range from 1 to 15 %. Compared with other published analytical procedures, the present method enables the simultaneous determination of a couple of phenolic agents with competitive or improved analytical reliability. Thus, the present method is suitable for a combined monitoring of the exposure to prominent xenobiotics with effects on the human endocrine system (bisphenol A, carbaryl, chlorpyrifos, chlorpyrifos-methyl, naphthalene, propoxur, triclopyr) and phytoestrogens (daidzein, genistein) in population studies.

[Pharmacokinetics of genistein in urine of healthy volunteers].

In order to study the excretion of genistein (GEN) capsule, an estrogen drugs, in human, 30 healthy volunteers were selected and orally administered 50, 100, and 300 mg genistein in an parallel study. Genistein were determined in urine by LC-MS/MS and glucuronidated genistein (GENG) were indirectly determined with enzymatic hydrolysis in urine by LC-MS/MS, and the pharmacokinetic parameters were analyzed by DAS software (ver 2.0). The result showed that the concentrations of genistein in human urine were less than 1% of the GENG, and the cumulative excretion of GEN in 48 h were 0.037, 0.134, and 0.142 mg, separately, and the urinary excretion percentage were only 0.07%, 0.13%, and 0.05%, separately. But the cumulative excretion of GENG in 48 h was 5.3, 13.8, and 15.4 mg, separately, and the urinary excretion percentage were 10.6%, 13.8%, and 5.1%, separately, and the max urinary excretive rate was 0.4, 1.0, and 1.4 mg x h(-1), separately (tmax were 6 h). Studies showed that part of drug excreted through kidney in a form of GENG in human, and the cumulative urinary excretion and the maximum excretion rate of GENG showed a proportional increase conditioned with the dose in the range of 50-100 mg, but showed non-linear increase feature in 300 mg.

Metabolism and disposition of isoflavone conjugated metabolites in humans after ingestion of kinako.

Isoflavone aglycones daidzein (Dein) and genistein (Gein) are present primarily as glucuronides and sulfates in human plasma; however, very little is known about the plasma pharmacokinetics of isoflavone conjugates after soy ingestion. The aim of this study was to investigate metabolism and disposition of the isoflavone conjugated metabolites glucuronide or sulfate or both after ingestion of kinako (baked soybean flour) by 10 volunteers. The quantifications of 16 metabolites in plasma and urine were performed by our previously reported high-performance liquid chromatography-UV-diode-array detector method. Plasma concentrations of total Dein and Gein metabolites reached maximal values of 0.64 ± 0.18 µM at 4.7 ± 2.5 h and 1.58 ± 0.55 µM at 5.4 ± 2.1 h, respectively. The area under the curve from 0 to 48 h demonstrated that daidzein-7-glucuronide-4'-sulfate (D-7G-4'S) (53.3%) was a major metabolite of Dein and that genistein-7-glucuronide-4'-sulfate (G-7G-4'S) (54.0%) and genistein-4',7-diglucuronide (G-4',7-diG) (26.6%) were major metabolites of Gein in plasma. The compositions of isoflavone metabolites in urine and plasma were greatly different. Approximately half of the 48-h urinary excretion of total Dein metabolites consisted of daidzein-7-glucuronide. The total amounts of genistein-7-glucuronide and genistein-4'-glucuronide were half the total amount of the urinary Gein metabolites. Excretion into urine of D-7G-4'S and G-7G-4'S accounted for only 16% each of the total Dein and Gein metabolites, respectively. The plasma and urine profiles of 16 metabolites of Dein and Gein demonstrate the involvement of desulfation and deglucuronidation of the conjugated metabolites D-7G-4'S, G-7G-4'S, and G-4',7-diG in the process of renal excretion.

Apparent bioavailability of isoflavones in urinary excretions of postmenopausal Malay women consuming tempeh compared with milk.

Quantitation of isoflavones in humans is important to establish the benefits of these compounds to the populations. Urinary isoflavones are frequently used as a biomarker of isoflavone bioavailability from food or supplement since urine contains 100-fold higher concentrations of isoflavones. The objective of the present study was to determine and compare the urinary excretions of daidzein (DA), genistein (GE) and equol (EQ) in postmenopausal Malay women following the consumption of tempeh and milk in a calcium absorption study and to test the hypothesis that the excretion of isoflavones following consumption of tempeh maybe higher compared with milk. The amounts of DA (47.06 ± 4.18 µmol/h), GE (33.27 ± 3.71 µmol/h) and EQ (24.35 ± 4.34 µmol/h) excreted in urine following tempeh consumption were significantly higher (P < 0.05) compared with those in milk (3.51 ± 0.62 µmol/h DA, 2.79 ± 0.35 µmol/h GE and 0 µmol/h EQ). Almost all studied postmenopausal Malay women were able to excrete EQ following consumption of 240 g tempeh but only one subject can be classified as an equol producer. We concluded that most postmenopausal Malay women excreted DA, GE and EQ in their urine following tempeh consumption and the amount of the excreted isoflavones were higher compared with those in milk. However, further studies are needed to determine whether longer periods of time are required to capture EQ producers.

A Non-Probiotic Fermented Soy Product Reduces Total and LDL Cholesterol: A Randomized Controlled Crossover Trial.

Traditional Asian fermented soy food products are associated with reduced cardiovascular disease risk in prospective studies, but few randomized controlled trials have been conducted in at-risk populations. The aim of this study was to investigate the effect of a commercial non-probiotic fermented soy product on blood lipids in adults with cardiovascular risk biomarkers. In a randomized, crossover, intervention study, 27 men and women (aged 29-75 y) exhibiting at least two risk factors, consumed two packets (12.5 g each) daily of a fermented powdered soy product, or an isoenergic control powder made from germinated brown rice for 12 weeks each. The consumption of the fermented soy product resulted in a significantly greater mean change from baseline (compared to the germinated rice, all p < 0.05) in total cholesterol of -0.23 mmol/L (CI: -0.40, -0.06) compared with 0.14 mmol/L (CI: -0.03, 0.31), respectively; and low density lipoprotein (LDL) cholesterol -0.18 mmol/L (CI: -0.32, -0.04) compared with 0.04 mmol/L (CI: -0.01, 0.018) respectively. This was accompanied by an increase in high density lipoprotein (HDL) cholesterol in the germinated rice group, a decrease in apolipoprotein B (ApoB) in the fermented soy group, and a between-treatment effect in apolipoprotein A1 (ApoA1); however, the ratio of the LDL:HDL and of Apo B:ApoA1 did not differ between the groups. The ratio of total cholesterol:LDL decreased in men in the fermented soy group (p < 0.001). Twenty-four-hour urine collection at the end of each treatment period resulted in an increased excretion expressed as a ratio in µmol/d between treatments of 10.93 (CI: 5.07, 23.54) for daidzein; 1.24 (CI: 1.14, 4.43) for genistein; and, 8.48 (CI: 4.28, 16.80) for glycitein, all p < 0.05. The fermented soy powder consumed by participants in this study without implementing other changes in their typical diets, decreased the total and LDL cholesterol, and may serve as a dietary strategy to manage blood lipids. The trial was registered at ClinicalTrials.gov as NCT03429920.

Urinary phytoestrogens and risk of prostate cancer in Jamaican men.

We evaluated the relationship of spot urinary concentrations of phytoestrogens with total prostate cancer and tumor grade in a hospital-based case-control study in Jamaica. Urine samples were analyzed for genistein, daidzein, equol (isoflavones), and enterolactone (lignan) among newly diagnosed cases (n = 175) and controls (n = 194). Urinary concentrations of enterolactone (lignan) were higher among cases. There were no significant differences in median concentrations of isoflavone excretion. Compared with non-producers of equol (reference tertile), men who produced equol were at decreased risk of total prostate cancer (tertile 2: OR, 0.42; CI, 0.23-0.75) (tertile 3: OR, 0.48; CI, 0.26-0.87) (p (trend), 0.020) and high-grade disease (tertile 2: OR, 0.31; CI, 0.15-0.61) (tertile 3: OR, 0.29; CI, 0.13-0.60) (p (trend), 0.001). Higher concentrations of enterolactone were positively related to total prostate cancer (OR, 1.85; CI, 1.01-3.44; p (trend), 0.027) as well as high-grade disease (OR, 2.46; CI, 1.11-5.46; p (trend), 0.023). There were no associations between urinary excretion of genistein and daidzein with risk of prostate cancer. Producers of equol (isoflavone) may be at reduced risk of total- and high-grade prostate cancer whereas enterolactone may increase the likelihood of disease.

Simultaneous determination of formononetin, biochanin A and their active metabolites in human breast milk, saliva and urine using salting-out assisted liquid-liquid extraction and ultra high performance liquid chromatography-electrospray ionization tandem mass spectrum.

Isoflavonoid phytoestrogens, referred as "dietary estrogens" are widely distributed in the plant kingdom. Formononetin, biochanin A and their active metabolites daidzein and genistein are known to be the most potent among other isoflavonoid phytoestrogens. Thus there is a growing need to determine accurately their concentration in different biological fluids. In the present work, a sensitive analytical method was developed for the quantitative determination of these compounds in human breast milk, saliva and urine. The glycoside conjugates of these compounds were enzymatically hydrolysis prior to salting-out assisted liquid-liquid extraction. Quantitative analysis was done by ultra high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. The obtained results showed high correlation coefficients (r2 > 0.998) for the linear range established for formononetine, biochanin A, daidzein and genistein. The limits of detection (LODs) and low limits of quantitation (LLOQs) were in the ranges of 0.05-1.0 ng/mL and 1.0-4.0 ng/mL for all analytes in human biological fluids, respectively. The average recoveries ranged from 83.29% to 115.24% for the analytes with relative standard deviation (n = 5) values from 1.84% to 9.75% in samples. Both intra-day and inter-day precisions and accuracy were found to be within 12.53% and ± 12.92% respectively. Under different conditions of stability, the concentrations for four isoflavonoid phytoestrogens deviated within ±12.87% of norminal values. The developed method was successfully validated and applied to human breast milk, saliva and urine. The average concentrations of daidzein and genistein found in breast milk, saliva and urine samples ranged from 0 to 104.2 µg/kg, 18.17 to 786.0 µg/kg, 0 to 10974 µg/kg, respectively. Their presence in breast milk samples shows exposure of breast-fed baby to isoflavones. It also allows for the rapid screening of human biological fluids when testing for formononetin, biochanin A, daidzein and genistein production status in human.

Urinary phytoestrogen excretion and prostate cancer risk: a nested case-control study in the Multiethnic Cohort.

BACKGROUND: Phytoestrogens are of special interest in prostate cancer research because populations in Asia with a high consumption of phytoestrogens have a lower incidence of the disease than comparable populations in Western countries. METHODS: This case-control study is nested within a large multiethnic cohort in Hawaii and California. Urine samples were analysed for daidzein, genistein, equol, and enterolactone among 249 incident prostate cancer cases and 404 controls matched on age, race/ethnicity, date/time of specimen collection, and fasting status. RESULTS: The median excretion of daidzein was 0.173 nmol mg(-1) creatinine in cases and 0.291 in controls (P=0.01), and the median excretion of genistein was 0.048 in cases and 0.078 in controls (P=0.05). An inverse association was seen for daidzein overall (odds ratio for the highest vs lowest quintile=0.55, 95% confidence interval=0.31-0.98, P(trend)=0.03) and seemed to apply to localized (P(trend)=0.08) as well as advanced or high-grade cancer (P(trend)=0.09). This association was consistent across the four ethnic groups examined. Although the relationship was weaker for genistein, the odds ratios and trends were similarly inverse. Urinary excretion of equol and enterolactone was not significantly related to prostate cancer risk. CONCLUSION: Our findings suggest that high intake of isoflavones, as reflected by urinary excretion of daidzein and genistein, may be protective against prostate cancer.

Dietary seaweed modifies estrogen and phytoestrogen metabolism in healthy postmenopausal women.

Seaweed and soy foods are consumed daily in Japan, where breast cancer rates for postmenopausal women are significantly lower than in the West. Likely mechanisms include differences in diet, especially soy consumption, and estrogen metabolism. Fifteen healthy postmenopausal women participated in this double-blind trial of seaweed supplementation with soy challenge. Participants were randomized to 7 wk of either 5 g/d seaweed (Alaria) or placebo (maltodextrin). During wk 7, participants also consumed a daily soy protein isolate (2 mg isoflavones/kg body weight). After a 3-wk washout period, participants were crossed over to the alternate supplement schedule. There was an inverse correlation between seaweed dose (mg/kg body weight) and serum estradiol (E2) (seaweed-placebo = y = -2.29 x dose + 172.3; r = -0.70; P = 0.003), [corrected] which was linear across the range of weights. Soy supplementation increased urinary daidzein, glycitein, genistein, and O-desmethylangolensin (P = 0.0001) and decreased matairesinol and enterolactone (P < 0.05). Soy and seaweed plus soy (SeaSoy) increased urinary excretion of 2-hydroxyestrogen (2-OHE) (P = 0.0001) and the ratio of 2-OHE:16alpha-hydroxyestrone (16alphaOHE(1)) (P = 0.01). For the 5 equol excretors, soy increased urinary equol excretion (P = 0.0001); the combination of SeaSoy further increased equol excretion by 58% (P = 0.0001). Equol producers also had a 315% increase in 2:16 ratio (P = 0.001) with SeaSoy. Seaweed favorably alters estrogen and phytoestrogen metabolism and these changes likely include modulation of colonic bacteria.